In some types of building construction, the underside of the ceiling of the structure is insulated to prevent the loss of heat during the heating season. Also, in warmer climates, the insulation acts as a barrier to the infiltration of heat from the area above the ceiling. The ceiling structure is generally comprised of a plurality of parallel, evenly spaced rafters and a plurality of parallel, evenly spaced purlins or joists which are positioned spanning the rafters, and at right angles to the rafters. Typically, the ceiling joists are spaced on 2 foot centers.
Although most commercial construction uses metal rafters and joists or purlins, a significant component of the construction of such buildings uses wood for the joists. Typically, the insulation product designed for warm weather climates is faced with a foil-scrim-kraft facing. This facing has the layer of foil to act as a moisture and air infiltration barrier. It also serves as the finished ceiling.
Usually, the facing is designed to be wider than the insulation batt so that the flange can be used to staple the product into place. The use of wood joists enables the construction worker to apply the insulation from below the ceiling by stapling the flanges to the wooden joists, although other means of attachment, such as by adhesive, can be used. Typically, a 24 inch wide batt will have an extra 9 inches of facing (41/2 inches on each side) to provide for stapling to hold the batt in place between the joists. It is desirable in some climates to provide an R-19 insulation batt, which is nominally about 6 inches thick. In order to accommodate the typical 2.times.4 joist construction, the flange is designed to be wide enough to enable considerable sag of the facing material in order to enable the insulation material to fully expand to its six inch thickness.
One of the problems with typical extended flange batt products for the application to the undersides of ceiling structures is that the placement of the flange and stapling of the flange onto the joist is an imprecise craft. The typical installer never knows exactly how high to attach the flange onto the side of the joist. If the installer attaches the flange too far up on the joist, the facing is too taught, and the insulation product is compressed and not fully expanded. The resulting compressed insulation has lost some of its potential R-value. On the other hand, if the insulation installer attaches the facing too low on the joist, the facing will have too much sag, and air pathways, which provide thermal bridges for the entrance of heat will be established. This, of course, cuts down on the thermal performance of the insulation system.
The tendency during installation is for the installer to place the flange too high up on the joist in order to provide a relatively taught appearance of the bottom of the insulation product. Although this may be more aesthetically pleasing when viewed from below, it destroys some of the intended insulation value of the system.
In order to solve the problem of exact placement of the product flange on the sidewall of the joist, any mark or indication on the flange must meet several requirements, first, it must be visible from both the top and bottom side of the flange so that the installer has the flexibility of stapling on either side of the flange. Second, it is highly desirable for any such indicator to be substantially invisible to the viewer standing on the ground beneath the ceiling in order to avoid the appearance of a construction mark or blemish on the finished insulation system.
Another problem with extended flange insulation products is that when the flange is stapled to the joists, there is sometimes a tendency for the flange paper to rip or pull through the staple, with the result being that the insulation product falls to the floor. Various attempts have been made to reinforce the area in which the flange is to be stapled so that the staple passes through a reinforcement fiber, thereby securely holding the flange into place.
It would be desirable to have a system for not only reinforcing the edges of the flange for strength in stapling, but also having some means for correctly informing the installer the exact desired location for the flange on the joist.